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.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
***********************************
Setting Up to Use the Yocto Project
***********************************
This chapter provides guidance on how to prepare to use the Yocto
Project. You can learn about creating a team environment to develop
using the Yocto Project, how to set up a :ref:`build
host <dev-manual/start:preparing the build host>`, how to locate
Yocto Project source repositories, and how to create local Git
repositories.
Creating a Team Development Environment
=======================================
It might not be immediately clear how you can use the Yocto Project in a
team development environment, or how to scale it for a large team of
developers. You can adapt the Yocto Project to many different use cases
and scenarios; however, this flexibility could cause difficulties if you
are trying to create a working setup that scales effectively.
To help you understand how to set up this type of environment, this
section presents a procedure that gives you information that can help
you get the results you want. The procedure is high-level and presents
some of the project's most successful experiences, practices, solutions,
and available technologies that have proved to work well in the past;
however, keep in mind, the procedure here is simply a starting point.
You can build off these steps and customize the procedure to fit any
particular working environment and set of practices.
1. *Determine Who is Going to be Developing:* You first need to
understand who is going to be doing anything related to the Yocto
Project and determine their roles. Making this determination is
essential to completing subsequent steps, which are to get your
equipment together and set up your development environment's
hardware topology.
Here are possible roles:
- *Application Developer:* This type of developer does application
level work on top of an existing software stack.
- *Core System Developer:* This type of developer works on the
contents of the operating system image itself.
- *Build Engineer:* This type of developer manages Autobuilders and
releases. Depending on the specifics of the environment, not all
situations might need a Build Engineer.
- *Test Engineer:* This type of developer creates and manages
automated tests that are used to ensure all application and core
system development meets desired quality standards.
2. *Gather the Hardware:* Based on the size and make-up of the team,
get the hardware together. Ideally, any development, build, or test
engineer uses a system that runs a supported Linux distribution.
These systems, in general, should be high performance (e.g. dual,
six-core Xeons with 24 Gbytes of RAM and plenty of disk space). You
can help ensure efficiency by having any machines used for testing
or that run Autobuilders be as high performance as possible.
.. note::
Given sufficient processing power, you might also consider
building Yocto Project development containers to be run under
Docker, which is described later.
3. *Understand the Hardware Topology of the Environment:* Once you
understand the hardware involved and the make-up of the team, you
can understand the hardware topology of the development environment.
You can get a visual idea of the machines and their roles across the
development environment.
4. *Use Git as Your Source Control Manager (SCM):* Keeping your
:term:`Metadata` (i.e. recipes,
configuration files, classes, and so forth) and any software you are
developing under the control of an SCM system that is compatible
with the OpenEmbedded build system is advisable. Of all of the SCMs
supported by BitBake, the Yocto Project team strongly recommends using
:ref:`overview-manual/development-environment:git`.
Git is a distributed system
that is easy to back up, allows you to work remotely, and then
connects back to the infrastructure.
.. note::
For information about BitBake, see the
:doc:`bitbake:index`.
It is relatively easy to set up Git services and create
infrastructure like :yocto_git:`/`, which is based on
server software called ``gitolite`` with ``cgit`` being used to
generate the web interface that lets you view the repositories. The
``gitolite`` software identifies users using SSH keys and allows
branch-based access controls to repositories that you can control as
little or as much as necessary.
.. note::
The setup of these services is beyond the scope of this manual.
However, here are sites describing how to perform setup:
- `Gitolite <https://gitolite.com>`__: Information for
``gitolite``.
- `Interfaces, frontends, and
tools <https://git.wiki.kernel.org/index.php/Interfaces,_frontends,_and_tools>`__:
Documentation on how to create interfaces and frontends for
Git.
5. *Set up the Application Development Machines:* As mentioned earlier,
application developers are creating applications on top of existing
software stacks. Following are some best practices for setting up
machines used for application development:
- Use a pre-built toolchain that contains the software stack
itself. Then, develop the application code on top of the stack.
This method works well for small numbers of relatively isolated
applications.
- Keep your cross-development toolchains updated. You can do this
through provisioning either as new toolchain downloads or as
updates through a package update mechanism using ``opkg`` to
provide updates to an existing toolchain. The exact mechanics of
how and when to do this depend on local policy.
- Use multiple toolchains installed locally into different
locations to allow development across versions.
6. *Set up the Core Development Machines:* As mentioned earlier, core
developers work on the contents of the operating system itself.
Following are some best practices for setting up machines used for
developing images:
- Have the :term:`OpenEmbedded Build System` available on
the developer workstations so developers can run their own builds
and directly rebuild the software stack.
- Keep the core system unchanged as much as possible and do your
work in layers on top of the core system. Doing so gives you a
greater level of portability when upgrading to new versions of
the core system or Board Support Packages (BSPs).
- Share layers amongst the developers of a particular project and
contain the policy configuration that defines the project.
7. *Set up an Autobuilder:* Autobuilders are often the core of the
development environment. It is here that changes from individual
developers are brought together and centrally tested. Based on this
automated build and test environment, subsequent decisions about
releases can be made. Autobuilders also allow for "continuous
integration" style testing of software components and regression
identification and tracking.
See ":yocto_ab:`Yocto Project Autobuilder <>`" for more
information and links to buildbot. The Yocto Project team has found
this implementation works well in this role. A public example of
this is the Yocto Project Autobuilders, which the Yocto Project team
uses to test the overall health of the project.
The features of this system are:
- Highlights when commits break the build.
- Populates an :ref:`sstate
cache <overview-manual/concepts:shared state cache>` from which
developers can pull rather than requiring local builds.
- Allows commit hook triggers, which trigger builds when commits
are made.
- Allows triggering of automated image booting and testing under
the QuickEMUlator (QEMU).
- Supports incremental build testing and from-scratch builds.
- Shares output that allows developer testing and historical
regression investigation.
- Creates output that can be used for releases.
- Allows scheduling of builds so that resources can be used
efficiently.
8. *Set up Test Machines:* Use a small number of shared, high
performance systems for testing purposes. Developers can use these
systems for wider, more extensive testing while they continue to
develop locally using their primary development system.
9. *Document Policies and Change Flow:* The Yocto Project uses a
hierarchical structure and a pull model. There are scripts to create and
send pull requests (i.e. ``create-pull-request`` and
``send-pull-request``). This model is in line with other open source
projects where maintainers are responsible for specific areas of the
project and a single maintainer handles the final "top-of-tree"
merges.
.. note::
You can also use a more collective push model. The ``gitolite``
software supports both the push and pull models quite easily.
As with any development environment, it is important to document the
policy used as well as any main project guidelines so they are
understood by everyone. It is also a good idea to have
well-structured commit messages, which are usually a part of a
project's guidelines. Good commit messages are essential when
looking back in time and trying to understand why changes were made.
If you discover that changes are needed to the core layer of the
project, it is worth sharing those with the community as soon as
possible. Chances are if you have discovered the need for changes,
someone else in the community needs them also.
10. *Development Environment Summary:* Aside from the previous steps,
here are best practices within the Yocto Project development
environment:
- Use :ref:`overview-manual/development-environment:git` as the source control
system.
- Maintain your Metadata in layers that make sense for your
situation. See the ":ref:`overview-manual/yp-intro:the yocto project layer model`"
section in the Yocto Project Overview and Concepts Manual and the
":ref:`dev-manual/layers:understanding and creating layers`"
section for more information on layers.
- Separate the project's Metadata and code by using separate Git
repositories. See the ":ref:`overview-manual/development-environment:yocto project source repositories`"
section in the Yocto Project Overview and Concepts Manual for
information on these repositories. See the
":ref:`dev-manual/start:locating yocto project source files`"
section for information on how to set up local Git repositories
for related upstream Yocto Project Git repositories.
- Set up the directory for the shared state cache
(:term:`SSTATE_DIR`) where
it makes sense. For example, set up the sstate cache on a system
used by developers in the same organization and share the same
source directories on their machines.
- Set up an Autobuilder and have it populate the sstate cache and
source directories.
- The Yocto Project community encourages you to send patches to the
project to fix bugs or add features. If you do submit patches,
follow the project commit guidelines for writing good commit
messages. See the ":doc:`../contributor-guide/submit-changes`"
section in the Yocto Project and OpenEmbedded Contributor Guide.
- Send changes to the core sooner than later as others are likely
to run into the same issues. For some guidance on mailing lists
to use, see the lists in the
":ref:`contributor-guide/submit-changes:finding a suitable mailing list`"
section. For a description
of the available mailing lists, see the ":ref:`resources-mailinglist`" section in
the Yocto Project Reference Manual.
Preparing the Build Host
========================
This section provides procedures to set up a system to be used as your
:term:`Build Host` for
development using the Yocto Project. Your build host can be a native
Linux machine (recommended), it can be a machine (Linux, Mac, or
Windows) that uses `CROPS <https://github.com/crops/poky-container>`__,
which leverages `Docker Containers <https://www.docker.com/>`__ or it
can be a Windows machine capable of running Windows Subsystem For Linux
v2 (WSL).
.. note::
The Yocto Project is not compatible with
`Windows Subsystem for Linux v1 <https://en.wikipedia.org/wiki/Windows_Subsystem_for_Linux>`__.
It is compatible but not officially supported nor validated with
WSLv2. If you still decide to use WSL please upgrade to
`WSLv2 <https://docs.microsoft.com/en-us/windows/wsl/install-win10>`__.
Once your build host is set up to use the Yocto Project, further steps
are necessary depending on what you want to accomplish. See the
following references for information on how to prepare for Board Support
Package (BSP) development and kernel development:
- *BSP Development:* See the ":ref:`bsp-guide/bsp:preparing your build host to work with bsp layers`"
section in the Yocto Project Board Support Package (BSP) Developer's
Guide.
- *Kernel Development:* See the ":ref:`kernel-dev/common:preparing the build host to work on the kernel`"
section in the Yocto Project Linux Kernel Development Manual.
Setting Up a Native Linux Host
------------------------------
Follow these steps to prepare a native Linux machine as your Yocto
Project Build Host:
1. *Use a Supported Linux Distribution:* You should have a reasonably
current Linux-based host system. You will have the best results with
a recent release of Fedora, openSUSE, Debian, Ubuntu, RHEL or CentOS
as these releases are frequently tested against the Yocto Project and
officially supported. For a list of the distributions under
validation and their status, see the ":ref:`Supported Linux
Distributions <detailed-supported-distros>`"
section in the Yocto Project Reference Manual and the wiki page at
:yocto_wiki:`Distribution Support </Distribution_Support>`.
2. *Have Enough Free Memory:* Your system should have at least 50 Gbytes
of free disk space for building images.
3. *Meet Minimal Version Requirements:* The OpenEmbedded build system
should be able to run on any modern distribution that has the
following versions for Git, tar, Python and gcc.
- Git &MIN_GIT_VERSION; or greater
- tar &MIN_TAR_VERSION; or greater
- Python &MIN_PYTHON_VERSION; or greater.
- gcc &MIN_GCC_VERSION; or greater.
If your build host does not meet any of these listed version
requirements, you can take steps to prepare the system so that you
can still use the Yocto Project. See the
":ref:`ref-manual/system-requirements:required git, tar, python and gcc versions`"
section in the Yocto Project Reference Manual for information.
4. *Install Development Host Packages:* Required development host
packages vary depending on your build host and what you want to do
with the Yocto Project. Collectively, the number of required packages
is large if you want to be able to cover all cases.
For lists of required packages for all scenarios, see the
":ref:`ref-manual/system-requirements:required packages for the build host`"
section in the Yocto Project Reference Manual.
Once you have completed the previous steps, you are ready to continue
using a given development path on your native Linux machine. If you are
going to use BitBake, see the
":ref:`dev-manual/start:cloning the \`\`poky\`\` repository`"
section. If you are going
to use the Extensible SDK, see the ":doc:`/sdk-manual/extensible`" Chapter in the Yocto
Project Application Development and the Extensible Software Development
Kit (eSDK) manual. If you want to work on the kernel, see the :doc:`/kernel-dev/index`. If you are going to use
Toaster, see the ":doc:`/toaster-manual/setup-and-use`"
section in the Toaster User Manual.
Setting Up to Use CROss PlatformS (CROPS)
-----------------------------------------
With `CROPS <https://github.com/crops/poky-container>`__, which
leverages `Docker Containers <https://www.docker.com/>`__, you can
create a Yocto Project development environment that is operating system
agnostic. You can set up a container in which you can develop using the
Yocto Project on a Windows, Mac, or Linux machine.
Follow these general steps to prepare a Windows, Mac, or Linux machine
as your Yocto Project build host:
1. *Determine What Your Build Host Needs:*
`Docker <https://www.docker.com/what-docker>`__ is a software
container platform that you need to install on the build host.
Depending on your build host, you might have to install different
software to support Docker containers. Go to the Docker installation
page and read about the platform requirements in "`Supported
Platforms <https://docs.docker.com/engine/install/#supported-platforms>`__"
your build host needs to run containers.
2. *Choose What To Install:* Depending on whether or not your build host
meets system requirements, you need to install "Docker CE Stable" or
the "Docker Toolbox". Most situations call for Docker CE. However, if
you have a build host that does not meet requirements (e.g.
Pre-Windows 10 or Windows 10 "Home" version), you must install Docker
Toolbox instead.
3. *Go to the Install Site for Your Platform:* Click the link for the
Docker edition associated with your build host's native software. For
example, if your build host is running Microsoft Windows Version 10
and you want the Docker CE Stable edition, click that link under
"Supported Platforms".
4. *Install the Software:* Once you have understood all the
pre-requisites, you can download and install the appropriate
software. Follow the instructions for your specific machine and the
type of the software you need to install:
- Install `Docker Desktop on
Windows <https://docs.docker.com/docker-for-windows/install/#install-docker-desktop-on-windows>`__
for Windows build hosts that meet requirements.
- Install `Docker Desktop on
MacOs <https://docs.docker.com/docker-for-mac/install/#install-and-run-docker-desktop-on-mac>`__
for Mac build hosts that meet requirements.
- Install `Docker Engine on
CentOS <https://docs.docker.com/engine/install/centos/>`__
for Linux build hosts running the CentOS distribution.
- Install `Docker Engine on
Debian <https://docs.docker.com/engine/install/debian/>`__
for Linux build hosts running the Debian distribution.
- Install `Docker Engine for
Fedora <https://docs.docker.com/engine/install/fedora/>`__
for Linux build hosts running the Fedora distribution.
- Install `Docker Engine for
Ubuntu <https://docs.docker.com/engine/install/ubuntu/>`__
for Linux build hosts running the Ubuntu distribution.
5. *Optionally Orient Yourself With Docker:* If you are unfamiliar with
Docker and the container concept, you can learn more here -
https://docs.docker.com/get-started/.
6. *Launch Docker or Docker Toolbox:* You should be able to launch
Docker or the Docker Toolbox and have a terminal shell on your
development host.
7. *Set Up the Containers to Use the Yocto Project:* Go to
https://github.com/crops/docker-win-mac-docs/wiki and follow
the directions for your particular build host (i.e. Linux, Mac, or
Windows).
Once you complete the setup instructions for your machine, you have
the Poky, Extensible SDK, and Toaster containers available. You can
click those links from the page and learn more about using each of
those containers.
Once you have a container set up, everything is in place to develop just
as if you were running on a native Linux machine. If you are going to
use the Poky container, see the
":ref:`dev-manual/start:cloning the \`\`poky\`\` repository`"
section. If you are going to use the Extensible SDK container, see the
":doc:`/sdk-manual/extensible`" Chapter in the Yocto
Project Application Development and the Extensible Software Development
Kit (eSDK) manual. If you are going to use the Toaster container, see
the ":doc:`/toaster-manual/setup-and-use`"
section in the Toaster User Manual.
Setting Up to Use Windows Subsystem For Linux (WSLv2)
-----------------------------------------------------
With `Windows Subsystem for Linux
(WSLv2) <https://docs.microsoft.com/en-us/windows/wsl/wsl2-about>`__,
you can create a Yocto Project development environment that allows you
to build on Windows. You can set up a Linux distribution inside Windows
in which you can develop using the Yocto Project.
Follow these general steps to prepare a Windows machine using WSLv2 as
your Yocto Project build host:
1. *Make sure your Windows 10 machine is capable of running WSLv2:*
WSLv2 is only available for Windows 10 builds > 18917. To check which
build version you are running, you may open a command prompt on
Windows and execute the command "ver".
::
C:\Users\myuser> ver
Microsoft Windows [Version 10.0.19041.153]
If your build is capable of running
WSLv2 you may continue, for more information on this subject or
instructions on how to upgrade to WSLv2 visit `Windows 10
WSLv2 <https://docs.microsoft.com/en-us/windows/wsl/wsl2-install>`__
2. *Install the Linux distribution of your choice inside Windows 10:*
Once you know your version of Windows 10 supports WSLv2, you can
install the distribution of your choice from the Microsoft Store.
Open the Microsoft Store and search for Linux. While there are
several Linux distributions available, the assumption is that your
pick will be one of the distributions supported by the Yocto Project
as stated on the instructions for using a native Linux host. After
making your selection, simply click "Get" to download and install the
distribution.
3. *Check your Linux distribution is using WSLv2:* Open a Windows
PowerShell and run::
C:\WINDOWS\system32> wsl -l -v
NAME STATE VERSION
*Ubuntu Running 2
Note the version column which says the WSL version
being used by your distribution, on compatible systems, this can be
changed back at any point in time.
4. *Optionally Orient Yourself on WSL:* If you are unfamiliar with WSL,
you can learn more here -
https://docs.microsoft.com/en-us/windows/wsl/wsl2-about.
5. *Launch your WSL Distibution:* From the Windows start menu simply
launch your WSL distribution just like any other application.
6. *Optimize your WSLv2 storage often:* Due to the way storage is
handled on WSLv2, the storage space used by the undelying Linux
distribution is not reflected immedately, and since bitbake heavily
uses storage, after several builds, you may be unaware you are
running out of space. WSLv2 uses a VHDX file for storage, this issue
can be easily avoided by manually optimizing this file often, this
can be done in the following way:
1. *Find the location of your VHDX file:*
First you need to find the distro app package directory, to achieve this
open a Windows Powershell as Administrator and run::
C:\WINDOWS\system32> Get-AppxPackage -Name "*Ubuntu*" | Select PackageFamilyName
PackageFamilyName
-----------------
CanonicalGroupLimited.UbuntuonWindows_79abcdefgh
You should now
replace the PackageFamilyName and your user on the following path
to find your VHDX file::
ls C:\Users\myuser\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79abcdefgh\LocalState\
Mode LastWriteTime Length Name
-a---- 3/14/2020 9:52 PM 57418973184 ext4.vhdx
Your VHDX file path is:
``C:\Users\myuser\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79abcdefgh\LocalState\ext4.vhdx``
2a. *Optimize your VHDX file using Windows Powershell:*
To use the ``optimize-vhd`` cmdlet below, first install the Hyper-V
option on Windows. Then, open a Windows Powershell as Administrator to
optimize your VHDX file, shutting down WSL first::
C:\WINDOWS\system32> wsl --shutdown
C:\WINDOWS\system32> optimize-vhd -Path C:\Users\myuser\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79abcdefgh\LocalState\ext4.vhdx -Mode full
A progress bar should be shown while optimizing the
VHDX file, and storage should now be reflected correctly on the
Windows Explorer.
2b. *Optimize your VHDX file using DiskPart:*
The ``optimize-vhd`` cmdlet noted in step 2a above is provided by
Hyper-V. Not all SKUs of Windows can install Hyper-V. As an alternative,
use the DiskPart tool. To start, open a Windows command prompt as
Administrator to optimize your VHDX file, shutting down WSL first::
C:\WINDOWS\system32> wsl --shutdown
C:\WINDOWS\system32> diskpart
DISKPART> select vdisk file="<path_to_VHDX_file>"
DISKPART> attach vdisk readonly
DISKPART> compact vdisk
DISKPART> exit
.. note::
The current implementation of WSLv2 does not have out-of-the-box
access to external devices such as those connected through a USB
port, but it automatically mounts your ``C:`` drive on ``/mnt/c/``
(and others), which you can use to share deploy artifacts to be later
flashed on hardware through Windows, but your build directory should
not reside inside this mountpoint.
Once you have WSLv2 set up, everything is in place to develop just as if
you were running on a native Linux machine. If you are going to use the
Extensible SDK container, see the ":doc:`/sdk-manual/extensible`" Chapter in the Yocto
Project Application Development and the Extensible Software Development
Kit (eSDK) manual. If you are going to use the Toaster container, see
the ":doc:`/toaster-manual/setup-and-use`"
section in the Toaster User Manual.
Locating Yocto Project Source Files
===================================
This section shows you how to locate, fetch and configure the source
files you'll need to work with the Yocto Project.
.. note::
- For concepts and introductory information about Git as it is used
in the Yocto Project, see the ":ref:`overview-manual/development-environment:git`"
section in the Yocto Project Overview and Concepts Manual.
- For concepts on Yocto Project source repositories, see the
":ref:`overview-manual/development-environment:yocto project source repositories`"
section in the Yocto Project Overview and Concepts Manual."
Accessing Source Repositories
-----------------------------
Working from a copy of the upstream :ref:`dev-manual/start:accessing source repositories` is the
preferred method for obtaining and using a Yocto Project release. You
can view the Yocto Project Source Repositories at
:yocto_git:`/`. In particular, you can find the ``poky``
repository at :yocto_git:`/poky`.
Use the following procedure to locate the latest upstream copy of the
``poky`` Git repository:
1. *Access Repositories:* Open a browser and go to
:yocto_git:`/` to access the GUI-based interface into the
Yocto Project source repositories.
2. *Select the Repository:* Click on the repository in which you are
interested (e.g. ``poky``).
3. *Find the URL Used to Clone the Repository:* At the bottom of the
page, note the URL used to clone that repository
(e.g. :yocto_git:`/poky`).
.. note::
For information on cloning a repository, see the
":ref:`dev-manual/start:cloning the \`\`poky\`\` repository`" section.
Accessing Index of Releases
---------------------------
Yocto Project maintains an Index of Releases area that contains related
files that contribute to the Yocto Project. Rather than Git
repositories, these files are tarballs that represent snapshots in time
of a given component.
.. note::
The recommended method for accessing Yocto Project components is to
use Git to clone the upstream repository and work from within that
locally cloned repository. However, this section documents how to
use a tarball snapshot of any given component.
Follow these steps to locate and download a particular tarball:
1. *Access the Index of Releases:* Open a browser and go to
:yocto_dl:`Index of Releases </releases>`. The
list represents released components (e.g. ``bitbake``, ``sato``, and
so on).
.. note::
The ``yocto`` directory contains the full array of released Poky
tarballs. The ``poky`` directory in the Index of Releases was
historically used for very early releases and exists now only for
retroactive completeness.
2. *Select a Component:* Click on any released component in which you
are interested (e.g. ``yocto``).
3. *Find the Tarball:* Drill down to find the associated tarball. For
example, click on ``yocto-&DISTRO;`` to view files associated with the
Yocto Project &DISTRO; release.
4. *Download the Tarball:* Click the tarball to download and save a
snapshot of the given component.
Using the Downloads Page
------------------------
The :yocto_home:`Yocto Project Website <>` uses a "DOWNLOADS" page
from which you can locate and download tarballs of any Yocto Project
release. Rather than Git repositories, these files represent snapshot
tarballs similar to the tarballs located in the Index of Releases
described in the ":ref:`dev-manual/start:accessing index of releases`" section.
1. *Go to the Yocto Project Website:* Open The
:yocto_home:`Yocto Project Website <>` in your browser.
2. *Get to the Downloads Area:* Select the "DOWNLOADS" item from the
pull-down "SOFTWARE" tab menu near the top of the page.
3. *Select a Yocto Project Release:* Use the menu next to "RELEASE" to
display and choose a recent or past supported Yocto Project release
(e.g. &DISTRO_NAME_NO_CAP;, &DISTRO_NAME_NO_CAP_MINUS_ONE;, and so forth).
.. note::
For a "map" of Yocto Project releases to version numbers, see the
:yocto_wiki:`Releases </Releases>` wiki page.
You can use the "RELEASE ARCHIVE" link to reveal a menu of all Yocto
Project releases.
4. *Download Tools or Board Support Packages (BSPs):* From the
"DOWNLOADS" page, you can download tools or BSPs as well. Just scroll
down the page and look for what you need.
Cloning and Checking Out Branches
=================================
To use the Yocto Project for development, you need a release locally
installed on your development system. This locally installed set of
files is referred to as the :term:`Source Directory`
in the Yocto Project documentation.
The preferred method of creating your Source Directory is by using
:ref:`overview-manual/development-environment:git` to clone a local copy of the upstream
``poky`` repository. Working from a cloned copy of the upstream
repository allows you to contribute back into the Yocto Project or to
simply work with the latest software on a development branch. Because
Git maintains and creates an upstream repository with a complete history
of changes and you are working with a local clone of that repository,
you have access to all the Yocto Project development branches and tag
names used in the upstream repository.
Cloning the ``poky`` Repository
-------------------------------
Follow these steps to create a local version of the upstream
:term:`Poky` Git repository.
1. *Set Your Directory:* Change your working directory to where you want
to create your local copy of ``poky``.
2. *Clone the Repository:* The following example command clones the
``poky`` repository and uses the default name "poky" for your local
repository::
$ git clone git://git.yoctoproject.org/poky
Cloning into 'poky'...
remote: Counting objects: 432160, done.
remote: Compressing objects: 100% (102056/102056), done.
remote: Total 432160 (delta 323116), reused 432037 (delta 323000)
Receiving objects: 100% (432160/432160), 153.81 MiB | 8.54 MiB/s, done.
Resolving deltas: 100% (323116/323116), done.
Checking connectivity... done.
Unless you
specify a specific development branch or tag name, Git clones the
"master" branch, which results in a snapshot of the latest
development changes for "master". For information on how to check out
a specific development branch or on how to check out a local branch
based on a tag name, see the
":ref:`dev-manual/start:checking out by branch in poky`" and
":ref:`dev-manual/start:checking out by tag in poky`" sections, respectively.
Once the local repository is created, you can change to that
directory and check its status. The ``master`` branch is checked out
by default::
$ cd poky
$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working directory clean
$ git branch
* master
Your local repository of poky is identical to the
upstream poky repository at the time from which it was cloned. As you
work with the local branch, you can periodically use the
``git pull --rebase`` command to be sure you are up-to-date
with the upstream branch.
Checking Out by Branch in Poky
------------------------------
When you clone the upstream poky repository, you have access to all its
development branches. Each development branch in a repository is unique
as it forks off the "master" branch. To see and use the files of a
particular development branch locally, you need to know the branch name
and then specifically check out that development branch.
.. note::
Checking out an active development branch by branch name gives you a
snapshot of that particular branch at the time you check it out.
Further development on top of the branch that occurs after check it
out can occur.
1. *Switch to the Poky Directory:* If you have a local poky Git
repository, switch to that directory. If you do not have the local
copy of poky, see the
":ref:`dev-manual/start:cloning the \`\`poky\`\` repository`"
section.
2. *Determine Existing Branch Names:*
::
$ git branch -a
* master
remotes/origin/1.1_M1
remotes/origin/1.1_M2
remotes/origin/1.1_M3
remotes/origin/1.1_M4
remotes/origin/1.2_M1
remotes/origin/1.2_M2
remotes/origin/1.2_M3
. . .
remotes/origin/thud
remotes/origin/thud-next
remotes/origin/warrior
remotes/origin/warrior-next
remotes/origin/zeus
remotes/origin/zeus-next
... and so on ...
3. *Check out the Branch:* Check out the development branch in which you
want to work. For example, to access the files for the Yocto Project
&DISTRO; Release (&DISTRO_NAME;), use the following command::
$ git checkout -b &DISTRO_NAME_NO_CAP; origin/&DISTRO_NAME_NO_CAP;
Branch &DISTRO_NAME_NO_CAP; set up to track remote branch &DISTRO_NAME_NO_CAP; from origin.
Switched to a new branch '&DISTRO_NAME_NO_CAP;'
The previous command checks out the "&DISTRO_NAME_NO_CAP;" development
branch and reports that the branch is tracking the upstream
"origin/&DISTRO_NAME_NO_CAP;" branch.
The following command displays the branches that are now part of your
local poky repository. The asterisk character indicates the branch
that is currently checked out for work::
$ git branch
master
* &DISTRO_NAME_NO_CAP;
Checking Out by Tag in Poky
---------------------------
Similar to branches, the upstream repository uses tags to mark specific
commits associated with significant points in a development branch (i.e.
a release point or stage of a release). You might want to set up a local
branch based on one of those points in the repository. The process is
similar to checking out by branch name except you use tag names.
.. note::
Checking out a branch based on a tag gives you a stable set of files
not affected by development on the branch above the tag.
1. *Switch to the Poky Directory:* If you have a local poky Git
repository, switch to that directory. If you do not have the local
copy of poky, see the
":ref:`dev-manual/start:cloning the \`\`poky\`\` repository`"
section.
2. *Fetch the Tag Names:* To checkout the branch based on a tag name,
you need to fetch the upstream tags into your local repository::
$ git fetch --tags
$
3. *List the Tag Names:* You can list the tag names now::
$ git tag
1.1_M1.final
1.1_M1.rc1
1.1_M1.rc2
1.1_M2.final
1.1_M2.rc1
.
.
.
yocto-2.5
yocto-2.5.1
yocto-2.5.2
yocto-2.5.3
yocto-2.6
yocto-2.6.1
yocto-2.6.2
yocto-2.7
yocto_1.5_M5.rc8
4. *Check out the Branch:*
::
$ git checkout tags/yocto-&DISTRO; -b my_yocto_&DISTRO;
Switched to a new branch 'my_yocto_&DISTRO;'
$ git branch
master
* my_yocto_&DISTRO;
The previous command creates and
checks out a local branch named "my_yocto_&DISTRO;", which is based on
the commit in the upstream poky repository that has the same tag. In
this example, the files you have available locally as a result of the
``checkout`` command are a snapshot of the "&DISTRO_NAME_NO_CAP;"
development branch at the point where Yocto Project &DISTRO; was
released.
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